Effect of aging temperature on microstructure and mechanical properties of direct quenched Ni-Cr-Mo-V-Cu steel

doi:10.13251/j.issn.0254-6051.2021.11.009

Abstract

Abstract: Effect of aging temperature on microstructure and mechanical properties of the direct quenched Ni-Cr-Mo-V-Cu low alloy steel was investigated by means of OM, SEM, TEM, physicochemical phase analysis and so on. At the same time, the yield strength model was established in the aged specimen with the best strength toughness matching. Microstructure of direct quenched Ni-Cr-Mo-V-Cu steel consists of martensite and a small amount of bainite. When the direct quenched Ni-Cr-Mo-V-Cu steel is aged in the range of 400 ℃ to 600 ℃ respectively, strength and Vickers hardness of the tested steel show typical under-aged state, peaking-aged state and over-aged state. The change of dislocation recovery, precipitation of MC and Cu-rich particles, desolvation of solid solution elements in bcc iron matrix and so on with aging temperature is responsible for the aged specimens showing the above three states. Elongation after fracture of the aged specimen generally improves with the increase of ageing temperature. Impact property at -20 ℃ of the over-aged specimen increases with the increase of ageing temperature. The direct quenched specimen aged at 600 ℃ shows superior combination of strength and toughness, and precipitating strengthening increment caused by MC and Cu-rich particles is about 240 MPa.

Key words: Cu-bearing low alloy steel, direct quenching, ageing, strengthening mechanism

CLC Number:

TG156.5

Zhu Fei, Luo Xiaobing, Yang Caifu, Chai Feng, Zhang Zhengyan. Effect of aging temperature on microstructure and mechanical properties of direct quenched Ni-Cr-Mo-V-Cu steel[J]. Heat Treatment of Metals, 2021, 46(11): 54-63.

References

[1]Liu Yongchang, Shi Lei, Liu Chenxi. Effect of step quenching on microstructures and mechanical properties of HSLA steel[J]. Materials Science and Engineering A, 2016, 675: 371-378.
[2]Liu Dongsheng, Li Qingliang, Emi Toshihiko. Microstructure and mechanical properties in hot-rolled extra high-yield-strength steel plates for offshore structure and shipbuilding[J]. Metallurgical and Materials Transactions A, 2010, 42(5): 1349-1361.
[3]Xi Xiaohui, Wang Jinliang, Li Xing. The role of intercritical annealing in enhancing low-temperature toughness of Fe-C-Mn-Ni-Cu structural steel[J]. Metallurgical and Materials Transactions A, 2019, 50(6): 2912-2921.
[4]Thompson S W. Microstructural characterization of an as-quenched HSLA-100 plate steel via transmission electron microscopy[J]. Materials Characterization, 2013, 77: 89-98.
[5]Mujahid Mohammad, Lis A K, Garcia C. HSLA steels: Microstructure and properties[J]. Key Engineering Materials, 1993, 84: 209-236.
[6]Takahashi J, Kawakami K, Kobayashi Y. Consideration of particle-strengthening mechanism of copper-precipitation-strengthened steels by atom probe tomography analysis[J]. Materials Science and Engineering A, 2012, 535: 144-152.
[7]Su Hang, Luo Xiaobing, Yang Caifu. Effects of cu on corrosion resistance of low alloyed steels in acid chloride media[J]. Journal of Iron and Steel Research, International, 2014, 21(6): 619-624.
[8]Hwang Guen Chul, Lee Sunghak, Yoo Jang Yong. Effect of direct quenching on microstructure and mechanical properties of copper-bearing high-strength alloy steels[J]. Materials Science and Engineering A, 1998, 252(2): 256-268.
[9]Yoo J, Choo W, Park T. Microstructures and age hardening characteristics of direct quenched Cu bearing HSLA steel[J]. ISIJ International, 1995, 35: 1034-1040.
[10]Dhua S K, Sen S K. Effect of direct quenching on the microstructure and mechanical properties of the lean-chemistry HSLA-100 steel plates[J]. Materials Science and Engineering A, 2011, 528(21): 6356-6365.
[11]Zhao Yu, Xu Songsong, Li Junpeng. Enhancement of low temperature toughness of nanoprecipitates strengthened ferritic steel by delamination structure[J]. Materials Science and Engineering A, 2017, 691: 162-167.
[12]杨才福, 张永权, 王瑞珍. 钒钢冶金原理与应用[M]. 北京: 冶金工业出版社, 2012: 51-76.
Yang Caifu, Zhang Yongquan, Wang Ruizhen. Metallurgical Principle and Application of Vanadium Steel[M]. Beijing: Metallurgical Industry Press, 2012: 51-76.
[13]Higginson R L, Sellars C M. Worked Examples in Quantitative Metallography[M]. London: Maney, 2003: 31-46.
[14]Jain Divya, Isheim Dieter, Hunter Allen. Multicomponent high-strength low-alloy steel precipitation-strengthened by sub-nanometric Cu precipitates and M₂C carbides[J]. Metallurgical and Materials Transactions A, 2016, 47(8): 1-13.
[15]Thompson S W. Fine-scale structural features of intercritically aged HSLA-100 plate steel and their influence on yield strength and low-temperature impact toughness[J]. Materials Characterization, 2018, 136: 425-434.
[16]雍岐龙. 钢铁材料中的第二相[M]. 北京: 冶金工业出版社, 2006: 1-204.
Yong Qilong. Second Phases in Structural Steels[M]. Beijing: Metallurgical Industry Press, 2006: 1-204.
[17]Kao A S, Kuhn H A, Richmond O. Tensile fracture and fractographic analysis of 1045 spheroidized steel under hydrostatic pressure[J]. Journal of Materials Research, 1990, 5(1): 83-91.
[18]Jiang Bo, Wu Meng, Zhang Mai. Microstructural characterization, strengthening and toughening mechanisms of a quenched and tempered steel: Effect of heat treatment parameters[J]. Materials Science and Engineering A, 2017, 707: 306-314.
[19]赵乃勤. 合金固态相变[M]. 长沙: 中南大学出版社, 2008: 255-265.
Zhao Naiqin. Solid Phase Transformation of Alloys[M]. Changsha: Central South University Press, 2008: 255-265.
[20]Chilton J M, Kelly P M. The strength of ferrous martensite[J]. Acta Metallurgica, 1968, 16(5): 637-656.
[21]张正延, 李昭东, 雍岐龙. 升温过程中Nb和Nb-Mo微合金化钢中碳化物的析出行为研究[J]. 金属学报, 2015, 51(3): 315-324.
Zhang Zhengyan, Li Zhaodong, Yong Qilong. Precipitation behavior of carbide during heating process in Nb and Nb-Mo micro-alloyed steels[J]. Acta Metallurgica Sinica, 2015, 51(3): 315-324.
[22]余永宁. 金属学原理[M]. 2版. 北京: 冶金工业出版社, 2013: 907-933.
Yu Yongning. Principles of Metals[M]. Second Edition. Beijing: Metallurgical Industry Press, 2013: 907-933.
[23]Yan Peng, Liu Zhengdong, Bao Hansheng. Effect of tempering temperature on the toughness of 9Cr-3W-3Co martensitic heat resistant steel[J]. Materials and Design, 2014, 54: 874-879.
[24]罗小兵, 杨才福, 苏航. 时效温度对HSLA高强船体钢组织和性能的影响[J]. 材料热处理学报, 2011, 32(6): 73-77.
Luo Xiaobing, Yang Caifu, Su Hang. Effect of aging temperature on microstructure and properties of HSLA ship-hull steel[J]. Transactions of Materials and Heat Treatment, 2011, 32(6): 73-77.
[25]余锡模, 赵世金. 含Cu和Ni低碳高强度钢等时回火析出富Cu相的研究[J]. 金属学报, 2013, 49(5): 569-575.
Yu Ximo, Zhao Shijin. Study on Cu precipitate of the low C high strength steel containing Cu and Ni during isochronal tempering[J]. Acta Metallurgica Sinica, 2013, 49(5): 569-575.
[26]Li Zhentuan, Chai Feng, Yang Li. Mechanical properties and nanoparticles precipitation behavior of multi-component ultra high strength steel[J]. Materials and Design, 2020, 191: 108637.
[27]Saastamoinen A, Kaijalainen A, Porter D. The effect of finish rolling temperature and tempering on the microstructure, mechanical properties and dislocation density of direct-quenched steel[J]. Materials Characterization, 2018, 139: 1-10.
[28]张正延, 柴锋, 罗小兵. 调质态含Cu高强钢的强化机理及钢中Cu的析出行为[J]. 金属学报, 2019, 55(6): 783-791.
Zhang Zhengyan, Chai Feng, Luo Xiaobing. The strengthening mechanism of Cu bearing high strength steel as-quenched and tempered and Cu precipitation behavior in steel[J]. Acta Metallurgica Sinica, 2019, 55(6): 783-791.